Adjustable propeller.



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SETE HART AND ROBERT I.v EUSTIS, F LOS ANGELES, CALIFORNIA.

ADJUSTABLE PltOPELLER.

Specification of Letters Patent.

Patentedv Apr. 15, 19,19.

Application' led September 10, 1917, Serial No. 190,527. Renewed March 4, 1919. Serial No. 280,661.

To all whom it may Concern.' j

Be it known that we, SETH HART and ROBERT l. EUsTIs, citizens of the United States, residing at Los Angeles, in the county of Los Angeles, State of/California, have invented new and useful Improvements in Adjustable Propellers, of which the followand produces very excellent results because I in is a specication.-

` his invention relates to propellers and particularly to adjustable or feathering propellers, and more particularly to such propellers designed for use on air craft; 'although, it will be understoodv that our invention is applicable to' propellers used in any medium.

For the purpose of describing our invention We herein explain a form of device particularly useful for airplanes, although it will be understood that ourinvention is not limited to such use.

ln airplanes and the like it is desirable that the pitch should be capable of 'being changed-that the angularity ofthe propeller blades should be capable of being 'chan-ged under the control of the aviator. We have found by actual trial and demonstration that an adjustabilit of propeller pitch is an exceptionally esirable Ything and so in actual practice the pitch of the propeller is xed .by a compromise. With an adjustably pitched propeller it is possi-- ble, and with our device it is thoroughly practical, to decrease the pitch when the machineis starting, enabling the machine to make a quick get-away; and to increase the pitch when the machine is flying, thus materially increasing the speed of flying With a given amount of power and atathe plane and at the same time to decrease the same time `decreasing the engine speed. In actualtest's we have been able to add as much as thirty per cent. to the speed of an airlt is an obj ect of this engine speed enough to materially reduce the engine vibration and add to the life of the engine;

invention to provide a' Simple and effective means for changing lthe pitch -of the propeller blade; to provide a means which is accurate, safe, andtrustworthy; one that does not weaken or otherwise have a detrimental eifect upon the pro'- peller construction itself; and also one which embodies a self-locking feature, and will hold the propeller blades in any adjusted position without any strain having to be borne by any part of the connective mechamsm.

`Our invention is characterized by the use of a. lsliding tilting rod .which engages the propeller blade, the blade being adjustably revoluble about an axis longitudinal of itself. Although it may be immaterial just where the sliding takes place, in practice We prefer to let the tilting rod slide through the blade base, the base `being preferably ro tatably mounted in a socket and preferably provided with an end thrust ball bearing to take the end thrust due to centrifugal force. The tilting rod has its end connected to a member movable to \and from the' blade, and normally stands in a position at an angle to the' line of said movement. Said member is preferably a slider movable longitudinally of the shaft; and longitudinal movements thereof cause relative sliding movement of the tilting rod and change the angular position of that rod and, thereby, the position of the blade. l

We illustrate a preferred form of device in the accompanying drawings wherein Figure l is an elevation of our improved propeller; Fig. 2 is Ian enlarged longitudinal section of the 4central Working parts of the propeller; Fig. 3 is a cross section taken as indicated by line 3-`3 on Fig. 2; and Fig. 4 is section taken as indicated by line 4-4 on Fig. 2.

In the drawings we show a propeller shaft at 10; lIn the preferred formyof. our improved propeller we provide a central. socket member 11 which may be mounted upon and connected to the shaft 10 by means of bolted flanges 12 and 13. The Hange 12 may preferably be formed integrally with the socket iet member 11; and, in our preferred construction, there are four reinforcing and way flanges 14 which extend from the liange 12 to the socket member 11 and may, if desired, overhang the flange 12 as shown at 14a so as to Provide the'desired length of way and at the same time allowing the iange 12`to be close to the socket member 11.

Our construction requires that thev pro 1 5 socketing the bases 16 of the propeller blades' within the oppositely projecting sockets of member 11. The sockets are not necessarilyT set opposite each other. We prefer this form, although any other suitable construc- V tion may be used whereby the propeller blades may be 'adj usted inthe manner herein stated. -Preferably we provide each base blade 16 with a sleeve 17 having a revolving fit in the socket 11. This sleeve 17 is permanently set upon blade base16; and this may be accomplished by enlarging the bore. of the sleeve at its inner end, as shown at 1-8, by driving into the wood of the propeller blade a tubular wedge 19 which causes the inner end of the base to expand in the manner indicated in the drawings. The sleeve 17 fits the base tightly and fits in the socket 11 as closely' as posslble consistent with free revolution.

To take care .of the outward end thrust due to centrifugal force, we provide end thrust ball bearings 20 which operate between a race ring 21 set upon the enlarged end 22 of sleeve 17 and a race ring 23 which has ascrew threaded mounting at 24 on to the end of socket 11; and a pin, as shown'at l 25, or any other suitable means. may be used, to prevent race ring 23 unscrewing from position. The race ring 21 has a conical bearingon the end 22 of sleeve 17 lso that it is automatically self-centering.

Upon the longitudinal way anges 14 we mount a slider 30 which is preferably in the form of a ring having notches as shown at 31 which engage the outer edges of the ways 14; and on two opposite sides this slider ring may have extended bosses 32 which provide extended bearings along two of the opposite way flanges 14. Now, although we describe this slider as preferably directly n'mounted upon flanges 14 which form a part of the central socket member of our device, yet this slider 30 may be sli'dably mounted on the shaft 10 in any suitable manner. Longitudinal/movementv of the slider causes the tilting movement of the blades inthe manner hereinafter described. This longif tudinal sliding movement is obtained through the medium of a npn-revolving ring o5 33 connected with the slider 30 through the j interposition--of a ball bearing 34. This .ball bearing may be, and preferably is, both a radial and end thrust bearing. The nonrevolving ring 33 isconnectedby pins 35 with a yoke 36. One side of Athis yoke 36 is 70 pivotednpon a pin 37 mounted upon any convenient, stationary bracket, as 38'; and the other side of the yoke is pivotally connected at 39 with a screw-threaded rod 40 threaded into a nut 41 preferably pivotally 75 Y' mounted `at 42. A swivel joint 43 is used on the rod 40 so that the rod may be rotated in the nut 41 to accurately adjust its longitudinal position and thus adjust the position of the yoke 36 and the longitudinal position 80 i .is bestl shown in FigQ'; and their ends are pivotally connected at 52 with-the slider 30. This pivotal connection. may be effectedby making the pivotal connection 52 to brackets 95 53 adjustablymounted on the slider ring 30; the brackets being adjustable parallel to the plane of the section in Fig. 3; so that by adjustment of the brackets a general permanent adjustment of theamount of tilt of rods 51 may be effected.

When the slider 30y is moved longitudinally and the -pivotal points 52 are moved to or from the blades, the rods`51 have a longitudinally sliding movement and at the 105v same time vchange their angular` position;

The amount of angular change depends upon the normal angularity of rods'51v and also upon the amount of movement of slider and we nd that it islnot necessary to -glve the rods 51 a great amount of normal augularity in` order to effect an adjustment movement of` suitable amount. Thus, with the rods in about the position shown in Fig.

A3, a relatively large sliding movement is thrust' bearing at 20) yet no amount of pressure lupon the blades themselvesl tending to displace them from their proper angular position will cause thesliding or longitudinal movement of rods 51 and slider 30. In 12.5

vother words, the sliding mechanism is selflocking in any position where it may be placed. This ease of adjusting movement and the fact that .the operator has a great leverage over any force which tends to oppose the adjusting movement of the blade, allows of a very .ine and accurate blade adjustment. By revolving the. screw 4:0 the operator gradually and smoothly changes the pitch of the blade. Furthermore, the self-locking feature of the device prevents any strain at all being imposed upon any of the parts other than thev tilting rods 51 and the slider all strain being kept 0H' the vconnective parts-36, 40, 44, etc. In fact, the

propeller blades ,may be so designed that there is very little force-exerted tending to move the blades from any'position in which they may be placed. But even this small force is transmitted no farther than the slider 30. The ball bearings at 34 are under no strain except during adjustment. When the movement is completed and theyoke- 36 is at rest,

then whatever pressure there was on the bearings during the adjustment'is immed ately relieved because ofthe fact that any vibration or pressure however slight, which has any tendencyto move the blades can yse only move them in the same direction as that in which the previous adjustment took place.

It will be seen that a distinctive feature of this mechanism is embodied in the ytilting rods which operate between the slider and the revoluble blades; having a pivoted or swinging connection at'one end and the slid ing connection at the other end.. For purposes of convenience in construction'andv operation we prefer to make the pivotal con- I nection at the slider end of each tilting rodand to have the rods slide through the blade but this arrangement may be reversed, if desired.

Further, our device is not limited in its application to a two blade propeller. It may be applied to any number of blades; for instance to \a propeller of four blades; and

where more than one pair of blades is used the blades,` the pairs of blades may be set in different planes of revolution (one set may be alittle farther along the shaft than another) so that all the blades do not rota tably cut through the same plane. And, although we illustrate our v propeller as a tractoi7 or puller propeller, it may be readily converted into a pusher by simpl withdrawing the rods 51 and turning eac blade over in Vits socket (turning each blade on its own longitudinal axis through 180). andvthen replacing the rods 51. This is an advantageous feature due tothe blades bes ing rotatable about their own axes.

The normal angularity of the bladestheir pitch -and their angularity at each extremity of adjustment will depend of course on the relative setting of the blades and thetilting rods and on the amount of angular adjusting movement given by the tilting rods.l The arrangement may enable the blades to be brought in fact to the zero angle-the position of nopitch-and even to reverse the pitch'for purposes of slowing I -down the airplane after landing, etc.

Although we have described a preferred f form of our device with some particularity' we do not thereby limit ourselves. Various' changes may be made in the specific construction, to adapt the device to dliferent situations, etc., without exceeding our invention as set forth in the following claims. Having described a preferred form o-f our invention, we claim: -1

bjustable therein about axes parallel to the blades, a shaft upon which the hub member is mounted, a guide structure integral with the hub member concentric around the shaft and projecting from the hub member parallel with the shaft, a slider on the guide structure slidable thereon and non-rotative with relation thereto, and diagonal slidable tilting rods pivotally attached to the slider and extending through the portions of the blades within the sockets, the sockets having slots through which the rods may pass.

3. In combination, a propeller shaft and a hub member having a radial blade Ireceiv. ing socket, a propeller blade having a base revolubly tting in the socket, an end-thrust bearing at the outer end of the socket to take the end-thrust of the blade due cocentrifugal force, a bearing sleeve extending transversely through the blade base between the ends of its bearin in the socket, a slider on and revoluble with the shaft, and an angularly disposed tilting rod pivoted to the slider and slidin through the bearing sleeve through the ladebase, the socket being slotted to pass the rod. v

4. In combination, a propeller lshaft and a -hub member having a radial blade receiv-v ing socket, a propeller blade with a base, av

bearing sleeve Irigidly mounted on the base and revolubly fitting in the socket, an end thrust bearing at the outer ends of the socket and bearing sleeve, a transverse bearing sleeve extending through the bladejbase and the first mentioned bearing sleeve between the ends of the socket, the socket being` slotted opposite the transverse bearing sleeve, a slidable angularly disposed tiltin rod passing through the socket slot and sli able through the transverse bearing sleeve,

a slider on and revoluble with the shaft, andpivotal connection between the slider and the rod.

5. In combination, a propeller shaft and a hub member havin la blade receiving socket, a propeller bla e having a base revolubly iitting in the socket, an end-thrust bearing to take the end thrust of the blade due to centrifugal force, the blade base having a transverse tilting rod passage through it between its'ends andv between the ends of the socket and the socket having a slot registering with the said passage, a slider revolving with the shaft and movable longitudinally thereof, and an angularly disposed tilting rod pivoted to the slider and sliding through the passage in th/eqblade ybase and through the socket slot. i

6. In combination, a propeller shaft and a hub member having a blade receiving socket, a propeller blade having a base revolubly fitting in the socket, an end thrust bearing to take the end thrust of the blade due to centrifugal force, a slider revolvin with the shaft and movable longitudinal y thereof, and aV tilting rod normally at an angle vto the lineof movement of the slider and connected at one end with lthe slider and connected at the other end with the blade base at a point between its ends and between the ends of the socket, one of said connections of said rod being a longitudinally sliding conend with the blade and at the other end with the sliding member, 'one of said connections ofy said rod being a longitudinal .Y

\sliding connection, and one of said connec- \tions of said rod being adjustable independently of the adjustmentin the sliding connection so as to adjust the normal posi u tion of the propeller blade.

In Witness that we claim the foregoing we have hereunto subscribed ournamesthis 4th da)7 of September and 28th day of August, 1917.

SETH RT.' ROBERT-I. EUSTIS.

Witness: A JAMES T. BARKELEW. 

